I'm attempting to fill a DataTable with results pulled from a MySQL database, however the DataTable, although it is initialised, doesn't populate. I wanted to use this DataTable to fill a ListView. Here's what I've got for the setting of the DataTable:
public DataTable SelectCharacters(string loginName)
{
this.Initialise();
string connection = "0.0.0.0";
string query = "SELECT * FROM characters WHERE _SteamName = '" + loginName + "'";
if (this.OpenConnection() == true)
{
MySqlCommand cmd = new MySqlCommand(query, connection);
MySqlDataAdapter returnVal = new MySqlDataAdapter(query,connection);
DataTable dt = new DataTable("CharacterInfo");
returnVal.Fill(dt);
this.CloseConnection();
return dt;
}
else
{
this.CloseConnection();
DataTable dt = new DataTable("CharacterInfo");
return dt;
}
}
And for the filling of the ListView, I've got:
private void button1_Click(object sender, EventArgs e)
{
string searchCriteria = textBox1.Text;
dt = characterDatabase.SelectCharacters(searchCriteria);
MessageBox.Show(dt.ToString());
listView1.View = View.Details;
ListViewItem iItem;
foreach (DataRow row in dt.Rows)
{
iItem = new ListViewItem();
for (int i = 0; i < row.ItemArray.Length; i++)
{
if (i == 0)
iItem.Text = row.ItemArray[i].ToString();
else
iItem.SubItems.Add(row.ItemArray[i].ToString());
}
listView1.Items.Add(iItem);
}
}
Is there something I'm missing? The MessageBox was included so I could see if it has populated, to no luck.
Thanks for any help you can give.
Check your connection string and instead of using
MySqlCommand cmd = new MySqlCommand(query, connection);
MySqlDataAdapter returnVal = new MySqlDataAdapter(query,connection);
DataTable dt = new DataTable("CharacterInfo");
returnVal.Fill(dt);
this.CloseConnection();
return dt;
you can use this one
MySqlCommand cmd = new MySqlCommand(query, connection);
DataTable dt = new DataTable();
dt.load(cmd.ExecuteReader());
return dt;
Well, I ... can't figure out what you have done here so I'll paste you my code with which I'm filling datagridview:
1) Connection should look something like this(if localhost is your server, else, IP adress of server machine):
string connection = #"server=localhost;uid=root;password=*******;database=*******;port=3306;charset=utf8";
2) Query is ok(it will return you something), but you shouldn't build SQL statements like that.. use parameters instead. See SQL injection.
3) Code:
void SelectAllFrom(string query, DataGridView dgv)
{
_dataTable.Clear();
try
{
_conn = new MySqlConnection(connection);
_conn.Open();
_cmd = new MySqlCommand
{
Connection = _conn,
CommandText = query
};
_cmd.ExecuteNonQuery();
_da = new MySqlDataAdapter(_cmd);
_da.Fill(_dataTable);
_cb = new MySqlCommandBuilder(_da);
dgv.DataSource = _dataTable;
dgv.DataMember = _dataTable.TableName;
dgv.AutoResizeColumns();
_conn.Close();
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
finally
{
if (_conn != null) _conn.Close();
}
}
So, every time I want to display some content of table in mysql database I call this method, pass query string and datagridview name to that method. and, that is it.
For your sake, compare this example with your and see what can you use from both of it. Maybe, listview is not the best thing for you, just saying ...
hope that this will help you a little bit.
Debug your application and see if your sql statement/ connection string is correct and returns some value, also verify if your application is not throwing any exception.
Your connection string is invalid.
Set it as follows:
connection = "Server=myServer;Database=myDataBase;Uid=myUser;Pwd=myPassword;";
Refer: mysql connection strings
Here the following why the codes would not work.
Connection
The connection of your mySQL is invalid
Query
I guess do you want to search in the table, try this query
string query = "SELECT * FROM characters WHERE _SteamName LIKE '" + loginName + "%'";
notice the LIKE and % this could help to list all the data. for more details String Comparison Functions
Related
I am creating an airline booking system and I have 2 combo boxes. The first is for Departure City and the second is for Arrival City. I want to be able to eliminate the choice in the first combo box from the second, as I don't want the same city to be able to be submitted as both the departure and arrival city. I am querying the city names from a database.
Here is my code:
public partial class main : Form
{
public main()
{
InitializeComponent();
string connectionString = #"Base Schema Name=cyanair;data source=C:\Users\Client 0819\source\repos\Cyanair\cyanair.db";
//Departure ComboBox
SQLiteConnection conn = new SQLiteConnection(connectionString);
try
{
conn.Open();
SQLiteCommand cmd = new SQLiteCommand();
cmd.Connection = conn;
cmd.CommandType = System.Data.CommandType.Text;
cmd.CommandText = "SELECT * FROM CyanairAirports";
SQLiteDataAdapter da = new SQLiteDataAdapter(cmd);
DataTable dt = new DataTable();
da.Fill(dt);
comboDeparture.DataSource = dt;
comboDeparture.ValueMember = "Descriptions";
comboDeparture.DisplayMember = "Descriptions";
conn.Close();
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
//Arrival ComboBox
private void comboDeparture_DisplayMemberChanged(object sender, EventArgs e)
{
string connectionString = #"Base Schema Name=cyanair;data source=C:\Users\Client 0819\source\repos\Cyanair\cyanair.db";
SQLiteConnection conn = new SQLiteConnection(connectionString);
**String city = comboDeparture.DisplayMember;**
try
{
conn.Open();
SQLiteCommand cmd = new SQLiteCommand();
cmd.Connection = conn;
cmd.CommandType = System.Data.CommandType.Text;
cmd.CommandText = "SELECT * FROM CyanairAirports WHERE Descriptions IS NOT '" + comboDeparture.SelectedValue.ToString() + "'";
richTextBox1.Text = "SELECT * FROM CyanairAirports WHERE Descriptions IS NOT '" + comboDeparture.SelectedValue + "'";
SQLiteDataAdapter da = new SQLiteDataAdapter(cmd);
DataTable dt = new DataTable();
da.Fill(dt);
comboArrival.DataSource = dt;
comboArrival.ValueMember = "Descriptions";
comboArrival.DisplayMember = "Descriptions";
conn.Close();
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
Thanks :)
It looks like you're handling the DisplayMemberChanged event on comboDeparture, and trying to update the values of comboArrival in that handler. However, DisplayMemberChanged only triggers when the DisplayMember property changes.
DisplayMember only tells the control which property to display on a data bound control. It isn't tied to the index or value selected in the ComboBox. So, the only time the code to populate comboArrival runs is in the constructor when you set comboDepartarture.DisplayMember. Instead, handle either ComboBox.SelectedIndexChanged or ComboBox.SelectedValueChanged and set the items of comboArrival.
A few other important things to note about your code.
First, you should use a parameterized query when running Sql Statements, rather than concatenating strings. Concatenating strings as you're doing opens you up to SQL Injection Attacks. I'm not familiar with SqlLite and can't provide you with an example of how to modify your code, but perhaps this question can help.
Second, you don't need to re-run the query every time you change the selected value in comboDeparture. Just add comboArrival's data source as a field on the Form and you can filter it. For example...
public partial class main : Form
{
// Your constructors...
private void comboDepartures_SelectedIndexChanged(object sender, EventArgs e)
{
if (_arrivalsDataSource == null)
{
_arrivalsDataSource = new System.Data.DataTable();
// Load _arrivalsDataSource from the database, basically how you're doing it now.
comboArrival.DataSource = _arrivalsDataSource.DefaultView;
comboArrival.DisplayMember = "Descriptions"
comboArribal.ValueMember = "Descriptions"
}
if (comboDeparture.SelectedIndex == -1)
{
_arrivalsDataSource.DefaultView.RowFilter = null; // Clear the filter.
}
else
{
// Set the filter.
_arrivalsDataSource.DefaultView.RowFilter = $"Description <> '{comboDeparture.SelectedValue}'";
}
}
private System.Data.DataTable _arrivalsDataSource = null;
}
I'm new to C#. I'm having a difficult time displaying my Access data in a DataTable. Here is the code:
try
{
reader.Read();
for (int i = 0; i < 16; i++)
{
if (selectedCourse == reader["CourseName"].ToString())
{
match = true;
}
else
{
match = false;
}
}
if (match == true)
{
tabControl.SelectedTab = tabPage1; // opens results page
string connString = #"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\Users\...454_Database.accdb";
DataTable results = new DataTable();
using (OleDbConnection conn = new OleDbConnection(connString))
{
OleDbCommand cmd = new OleDbCommand("Select c.PeriodID, c.CourseName, c.Teacher, t.Room"
+ "FROM Courses c JOIN Teacher t ON t.TeacherID = c.TeacherID"
+ "WHERE [CourseName] ='" + cboxClass.Text + "'", conn);
conn.Open();
OleDbDataAdapter adapter = new OleDbDataAdapter(cmd);
adapter.Fill(results);
dataTblResults.DataSource = results;
I can tell the data is being compared to the db and it correctly determines if the query has results or not. However, when there are results, they do not get displayed on the data table. Is it because it doesn't know which columns correspond to the columns in the data table?
Thanks in advance!
How is your datagrid configured?
Try setting: (before setting the DataSource)
dataTblResults.AutoGenerateColumns = true;
dataTblResults.DockStyle.Fill = DockStyle.Fill;
Try using a Dataset first. Then turn it to a datatable
DataSet ds = new DataSet();
adapter.fill(ds)
if (ds.Tables[0].Rows.Count >= 1)
{
results = ds.Tables[0];
}
dataTblResults.DataSource = results;
I dont think this is what you are looking for but maybe it'll bring you closer to the answer
this is a function for retrive two field in sql to combobox :
Code :
public void FillCmbKala()
{
cmbKala.Items.Clear();
objCon.Connecting();
string SQL = "SELECT [kID],[kName] FROM tblKala ORDER BY kName";
DataSet ds = new DataSet();
using (SqlConnection cn = new SqlConnection(objCon.StrCon))
{
using (SqlDataAdapter adapter = new SqlDataAdapter(SQL, cn))
{
cn.Open();
try
{
adapter.Fill(ds);
}
catch (SqlException e)
{
MessageBox.Show("There was an error accessing your data of 'Kala'. DETAIL: " + e.ToString());
}
finally
{
cn.Close();
}
}
}
cmbKala.DataSource = ds.Tables[0];
cmbKala.DisplayMember = "kName";
cmbKala.ValueMember = "kID";
}
when i use the combobox return System.Data.DataRowView !
For Example :
string str= cmbKala.SelectedItem;
result is : str= System.Data.DataRowView
Here is MSDN Reference.
As SelectedItem returns Object. It returns specific row object which is selected. Here is how you will get value:
DataRowView oDataRowView = cmbKala.SelectedItem as DataRowView;
string sValue = string.Empty;
if (oDataRowView != null) {
sValue = oDataRowView.Row["kName"] as string;
}
DataRowView dv = (DataRowView)comboBox1.SelectedItem;
string s = (string)dv.Row["kName"];
int m1 = (int)dv.Row["kID"];
The thing you are selecting IS a DataRowView. You should select the id of the item or the text instead right? Like string str= cmbKala.SelectedItem.Text or string str= cmbKala.SelectedItem.Value?
I know that this question is old, but I just wanted to let you guys know that If you get this error make sure you are using
ComboBoxName.DisplayMemberPath = "name of the column that you want to show in the combobox (ex: name)"
ComboBoxName.SelectedValuePath = "name of the column (ex:id)";
THIS WILL DEFINITELY HELP TO YOU
on the load Event you want to Just Write this code
onformload()
{
cmb_dept.Items.Clear();
SqlConnection conn = new SqlConnection(#"DATA SOURCE=(localdb)\MSSQLLocalDB;INTEGRATED SECURITY=true;INITIAL CATALOG=EMPLOYEE;");
conn.Open();
SqlCommand command = new SqlCommand("select dept_id, dept_name from department", conn);
SqlDataAdapter adapter = new SqlDataAdapter(command);
DataSet ds = new DataSet();
adapter.Fill(ds);
cmb_dept.ValueMember = "dept_id";
cmb_dept.DisplayMember = "dept_name";
cmb_dept.DataSource = ds.Tables[0];
}
try using Use the code where you want to access the values........
string dept = cmb_dept.Text; MessageBox.Show("val=" + dept);
YOUR combobox.text = System.Data.DataRowView Will be Solved ##
This works on C# WPF:
Textbox.Text = (listbox.SelectedItem as DataRowView).Row["Purpose"] as string;
I want to search some input in a data table and if exact data is found then I want to put those data into another table. If not, I will simply clear the corresponding TextBox. I have done theses so far.
private void btn_InputConfirm_Click(object sender, EventArgs e) {
string strConnection = #"Data Source=F_NOOB-PC\;Initial Catalog=ComShopDB;Integrated Security=True";
SqlConnection objcon = new SqlConnection(strConnection);
try {
string strcmd1 = "SELECT partID,partAvailable FROM Parts WHERE partID LIKE '" + txtbox_ProductSerial.Text + "'AND partAvailable ='yes'";
SqlCommand objcmd1 = new SqlCommand(strcmd1, objcon);
objcon.Open();
objcmd1.ExecuteNonQuery();
objcon.Close();
}
catch (Exception ex) {
MessageBox.Show(ex.Message);
}
}
Some help will be very much appreciated. Thanks in advance.
You can use a DataTable, use ExecuteReader method and load all records into DataTable, then use AsEnumerable and some LINQ you can get your results as a List.
DataTable dt = new DataTable();
var reader = objcmd1.ExecuteReader();
if(reader.HasRows)
{
dt.Load(reader);
var myValues = dt.AsEnumerable()
.Select(d => new {
Id = d["partID"],
Available = d["partAvailable"]
}).ToList();
}
Also you should consider using parameterized queries instead to prevent SQL Injection Attacks.
The easiest is to use DataAdapter and then use its Fill() function on a DataTable or DataSet. You do not need to open and close the connection as the Fill() function will do that for you:
private void btn_InputConfirm_Click(object sender, EventArgs e)
{
string strConnection = #"Data Source=F_NOOB-PC\;Initial Catalog=ComShopDB;Integrated Security=True";
SqlConnection objcon = new SqlConnection (strConnection);
try
{
//Writing command//
string strcmd1 = "SELECT partID,partAvailable FROM Parts WHERE partID LIKE '" + txtbox_ProductSerial.Text + "'AND partAvailable ='yes'";
System.Data.SqlClient.SqlDataAdapter da = new System.Data.SqlClient.SqlDataAdapter(strcmd1, objcon);
System.Data.DataSet ds = new System.Data.DataSet();
aa.Fill(ds);
}
catch ( Exception ex )
{
MessageBox.Show (ex.Message);
}
I have filled a DataSet with a Table that was created from another database file. The table is NOT in the database file which I want to be able to copy the Table to.
Now I want to save all those records (DataTable) to a newly created SQLite database file...
How can i do that?
Also I really want to avoid loops if this is possible.
The best answer is by me :) so i'll share it.This is loop but writes 100k entries in 2-3secs.
using (DbTransaction dbTrans = kaupykliuduomConn.BeginTransaction())
{
downloadas.Visible = true; //my progressbar
downloadas.Maximum = dataSet1.Tables["duomenys"].Rows.Count;
using (DbCommand cmd = kaupykliuduomConn.CreateCommand())
{
cmd.CommandText = "INSERT INTO duomenys(Barkodas, Preke, kiekis) VALUES(?,?,?)";
DbParameter Field1 = cmd.CreateParameter();
DbParameter Field2 = cmd.CreateParameter();
DbParameter Field3 = cmd.CreateParameter();
cmd.Parameters.Add(Field1);
cmd.Parameters.Add(Field2);
cmd.Parameters.Add(Field3);
while (n != dataSet1.Tables["duomenys"].Rows.Count)
{
Field1.Value = dataSet1.Tables["duomenys"].Rows[n]["Barkodas"].ToString();
Field2.Value = dataSet1.Tables["duomenys"].Rows[n]["Preke"].ToString();
Field3.Value = dataSet1.Tables["duomenys"].Rows[n]["kiekis"].ToString();
downloadas.Value = n;
n++;
cmd.ExecuteNonQuery();
}
}
dbTrans.Commit();
}
In this case dataSet1.Tables["duomenys"] is already filled with all the data i need to transfer to another database. I used loop to fill dataset too.
When you load the DataTable from the source database, set the AcceptChangesDuringFill property of the data adapter to false, so that loaded records are kept in the Added state (assuming that the source database is SQL Server)
var sqlAdapter = new SqlDataAdapter("SELECT * FROM the_table", sqlConnection);
DataTable table = new DataTable();
sqlAdapter.AcceptChangesDuringFill = false;
sqlAdapter.Fill(table);
Create the table in the SQLite database, by executing the CREATE TABLE statement directly with SQLiteCommand.ExecuteNonQuery
Create a new DataAdapter for the SQLite database connection, and use it to Update the db:
var sqliteAdapter = new SQLiteDataAdapter("SELECT * FROM the_table", sqliteConnection);
var cmdBuilder = new SQLiteCommandBuilder(sqliteAdapter);
sqliteAdapter.Update(table);
If the source and target tables have the same column names and compatible types, it should work fine...
The way to import SQL data to SQLite will take long time. When you want to import data in millions, It will take lot of time. So the shortest and easiest way to do that is just fill fetch the data from SQL database in a DataTable and insert all its rows to SQLite database.
public bool ImportDataToSQLiteDatabase(string Proc, string SQLiteDatabase, params object[] obj)
{
DataTable result = null;
SqlConnection conn = null;
SqlCommand cmd = null;
try
{
result = new DataTable();
using (conn = new SqlConnection(ConStr))
{
using (cmd = CreateCommand(Proc, CommandType.StoredProcedure, obj))
{
cmd.Connection = conn;
conn.Open();
result.Load(cmd.ExecuteReader());
}
}
using (SQLiteConnection con = new SQLiteConnection(string.Format("Data Source={0};Version=3;New=False;Compress=True;Max Pool Size=100;", SQLiteDatabase)))
{
con.Open();
using (SQLiteTransaction transaction = con.BeginTransaction())
{
foreach (DataRow row in result.Rows)
{
using (SQLiteCommand sqlitecommand = new SQLiteCommand("insert into table(fh,ch,mt,pn) values ('" + Convert.ToString(row[0]) + "','" + Convert.ToString(row[1]) + "','"
+ Convert.ToString(row[2]) + "','" + Convert.ToString(row[3]) + "')", con))
{
sqlitecommand.ExecuteNonQuery();
}
}
transaction.Commit();
new General().WriteApplicationLog("Data successfully imported.");
return true;
}
}
}
catch (Exception ex)
{
result = null;
return false;
}
finally
{
if (conn.State == ConnectionState.Open)
conn.Close();
}
}
It will take a very few time as compare to upper given answers.